Assessment of endometrial volume by three-dimensional ultrasound prior to embryo transfer: clues to endometrial receptivity.

The aim of the present prospective study was to obtain quantitative data on endometrial volume by three-dimensional (3D) ultrasound at the time of embryo transfer in an in-vitro fertilization programme and to assess its value in predicting endometrial receptivity. The cycles (n = 72) were classified according to endometrial volume: group A <2 ml, group B 2-4 ml, and group C >4 ml. Comparisons of the groups showed that pregnancy and implantation rates were significantly lower (P < 0.05) in the group of patients with an endometrial volume <2 ml. Furthermore, no pregnancy was achieved with an endometrial volume <1 ml. It is concluded that endometrial volume by 3D transvaginal ultrasound may become a new objective parameter by which to predict endometrial receptivity.